Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatri...Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatric population,phylogenetic relationships based on nrITS and cpDNA(rpl16)data,and complete chloroplast genome sequences.Comparative analysis of 21 morphological traits clearly separates the two varieties of H.elliptica.Examination of the flowering process and pollination treatments indicate that H.elliptica var.grandiflora produces seeds via outcrossing,whereas H.elliptica var.elliptica produces seeds via mixed mating.Furthermore,hand-pollinated hybridization of the two varieties produced no seeds.Observations of pollinators showed that when bees began a pollination bout on H.elliptica var.grandiflora they preferred to continue pollinating this variety;however,when they began a pollination bout on H.elliptica var.elliptica,they showed no preference for either variety.Phylogenetic analysis confirmed the monophyly of H.elliptica,which was further divided into two monophyletic clades corresponding to the two varieties.A large number of variants from the chloroplast genomes reflected remarkable genetic dissimilarities between the two varieties of H.elliptica.We recommend that the two varieties of H.elliptica should be revised as two species(H.elliptica and H.grandiflora).Our findings indicate that H.elliptica varieties may have split into two separate species due to a shift in mating system,changes in flowering phenology and/or post-pollination reproductive isolation.展开更多
Aims Sexual dimorphism is a common trait in plants with sex separation,which could influence female and male functions differently.In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau,we inves...Aims Sexual dimorphism is a common trait in plants with sex separation,which could influence female and male functions differently.In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau,we investigated sexual dimorphism of floral traits and their effects on pollinator visitation,pollen flow and seed production.We also examined differences in genome size of hermaphroditic and dioecious plants.Methods We examined sexual dimorphism in flower number,flower size,and pollen and ovule production in a subdioecious population of D.glabra.We compared pollinator visitation,pollen dispersal and seed production between sexes.We also examined the genome size of three sex morphs using flow cytometry.Important Findings The number of hermaphroditic plants was significantly more than that of male and female plants,and dioecious plants accounted for ca.40%in the study population.Hermaphroditic plants produced significantly more flowers than male and female plants.Flower size of male flowers was significantly larger than that of female and hermaphroditic flowers.Male flowers did not produce more pollen grains than hermaphroditic flowers,but female flowers produced more ovules than hermaphroditic flowers.Flies were the most frequent flower visitors and preferred large flowers,but their movements between flowers did not show any preference to large flowers.Simulated pollen flows suggested that effective pollen transfer was generally low for both hermaphroditic and male flowers,corresponding to the low seed set of naturally pollinated flowers.DNA contents of male and female plants were ca.four times than those of hermaphroditic plants.These results suggest male and female individuals have undergone polyploidy events and thus are not compatible with hermaphroditic individuals.Sexual dimorphism in floral traits in relation to pollination of dioecious plants might show an advantage in female and male functions,but this advantage is masked largely by low effectiveness of pollen transfer.展开更多
基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)National Key R&D Program of China(2017YFC0505200)+1 种基金National Natural Science Foundation of China(31460096 and 31590823)State Key Laboratory of Phytochemistry and Plant Resources in West China(P2020-KF04).
文摘Delimiting species requires multiple sources of evidence.Here,we delimited two varieties of Halenia elliptica(Gentianaceae)using several lines of evidence,including morphological traits and mating system in a sympatric population,phylogenetic relationships based on nrITS and cpDNA(rpl16)data,and complete chloroplast genome sequences.Comparative analysis of 21 morphological traits clearly separates the two varieties of H.elliptica.Examination of the flowering process and pollination treatments indicate that H.elliptica var.grandiflora produces seeds via outcrossing,whereas H.elliptica var.elliptica produces seeds via mixed mating.Furthermore,hand-pollinated hybridization of the two varieties produced no seeds.Observations of pollinators showed that when bees began a pollination bout on H.elliptica var.grandiflora they preferred to continue pollinating this variety;however,when they began a pollination bout on H.elliptica var.elliptica,they showed no preference for either variety.Phylogenetic analysis confirmed the monophyly of H.elliptica,which was further divided into two monophyletic clades corresponding to the two varieties.A large number of variants from the chloroplast genomes reflected remarkable genetic dissimilarities between the two varieties of H.elliptica.We recommend that the two varieties of H.elliptica should be revised as two species(H.elliptica and H.grandiflora).Our findings indicate that H.elliptica varieties may have split into two separate species due to a shift in mating system,changes in flowering phenology and/or post-pollination reproductive isolation.
基金by Natural Science Foundation of China(31570385).
文摘Aims Sexual dimorphism is a common trait in plants with sex separation,which could influence female and male functions differently.In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau,we investigated sexual dimorphism of floral traits and their effects on pollinator visitation,pollen flow and seed production.We also examined differences in genome size of hermaphroditic and dioecious plants.Methods We examined sexual dimorphism in flower number,flower size,and pollen and ovule production in a subdioecious population of D.glabra.We compared pollinator visitation,pollen dispersal and seed production between sexes.We also examined the genome size of three sex morphs using flow cytometry.Important Findings The number of hermaphroditic plants was significantly more than that of male and female plants,and dioecious plants accounted for ca.40%in the study population.Hermaphroditic plants produced significantly more flowers than male and female plants.Flower size of male flowers was significantly larger than that of female and hermaphroditic flowers.Male flowers did not produce more pollen grains than hermaphroditic flowers,but female flowers produced more ovules than hermaphroditic flowers.Flies were the most frequent flower visitors and preferred large flowers,but their movements between flowers did not show any preference to large flowers.Simulated pollen flows suggested that effective pollen transfer was generally low for both hermaphroditic and male flowers,corresponding to the low seed set of naturally pollinated flowers.DNA contents of male and female plants were ca.four times than those of hermaphroditic plants.These results suggest male and female individuals have undergone polyploidy events and thus are not compatible with hermaphroditic individuals.Sexual dimorphism in floral traits in relation to pollination of dioecious plants might show an advantage in female and male functions,but this advantage is masked largely by low effectiveness of pollen transfer.
